EP3258263B1

EP3258263B1 - Cell analyzer and particle sorting method and device

Info

Publication number: EP3258263B1
Application number: EP15881526.6A
Authority: EP
Inventors: Bo YE; Guanzhen WANG; Yi Ye; Jiantao DI; Ying Zhang; Huan Qi
Original assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Current assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Priority date: 2015-02-12
Filing date: 2015-02-12
Publication date: 2021-09-01
Anticipated expiration: 2035-02-12
Also published as: US20200191700A1; EP3258263A4; CN110244032B; CN110244032A; CN106662572A; WO2016127364A1; US10983042B2; US20200191701A1; EP3943912A1; US10883916B2; US20190277746A1; CN106662572B; EP3258263A1; US20170350804A1; US10627332B2; US10330584B2

Description

Technical Field

The present invention relates to a medical instrument, and more particularly to a cell analyser and a particle sorting method and device.

Background Art

A blood cell analyser is an instrument that can detect cells in the blood. It can count and sort cells such as leucocytes (white blood cells, WBC), red blood cells, blood platelets, nucleated red blood cells and reticulocytes.
The most common method used by a blood cell analyser to detect leucocytes is a laser scattering method, in which by irradiating cell particles flowing through a detection region with light, optical signals reflected or scattered by various categories of particles are collected, and then the optical signals are processed and analysed so as to sort and count the leucocytes. The collected optical signals may include three types of optical signals such as forward-scattered light, side-scattered light and fluorescence signals. The forward-scattered light can reflect size information of the cell, the side-scattered light can reflect complexity of an internal structure of the cell, and the fluorescence signal reflects the content of matters in the cell that can be dyed by a fluorescent dye, such as DNA and RNA. By means of these optical signals, the leucocytes can be sorted, and the leucocyte count can be obtained at the same time.
According to different pretreatments of blood samples (e.g., reagents being different), detection processes are divided into different detection channels, such as a DIFF channel, a BASO channel and a NRBC channel. The BASO channel is used to sort and count leucocytes, while a blood sample is treated with a chemical reagent, the total number of leucocytes is counted by means of side-scattered light and forward-scattered light, and a count of basophil granulocytes in the leucocytes is also provided. The NRBC channel can be used to sort nucleated red blood cells after a blood sample is treated with a fluorescent reagent added therein. The NRBC channel can provide a leucocyte count and a nucleated red blood cell count.
During blood cell detection by a blood cell analyser, two types of particles cannot be clearly distinguished from each other in some cases, thus affecting results of sorting the particles. For example, when counting leucocytes, the leucocytes may not be counted accurately due to the influence of interfering particles. The interfering particles may be lipid granules or aggregated PLT (blood platelet) particles. PLT is a part of a blood ghost which is a cell debris structure formed after a sample pretreatment of a blood sample, in which cells such as red blood cells or platelets are subjected to a hypotonic treatment or treated with a reagent, resulting in cell membrane rupture. Generally, the particle size is small, and the forward-scattered light signal is weak. However, in some samples, PLT aggregation may occur and interfering with the leucocyte detection. These interfering particles may overlap with the leucocyte in the scatter diagram. Fig. 1 shows a detection result of the NRBC channel, where an aggregated platelet cluster A1 overlaps with a leucocyte cluster B1 in the forward-scattered light and fluorescence signals. Fig. 2 shows a detection result of the BASO channel, where leucocytes are sorted into a basophil granulocyte cluster A2 and a cluster B2 of other leucocyte particles including lymphocytes, monocytes, neutrophil granulocytes and eosinophil granulocytes. Due to the exist of lipid particles, a lipid granule cluster C2 overlaps with the cluster B2 of other leucocyte particles in a region D2 at a lower end of the forward-scattered light and side-scattered light signals, which may interfere with counting of leucocytes. It can be seen that the exist of these interfering particles in the blood sample will affect the accuracy of the detection results.
US 2008/0176274 A1 describes a method for classifying and counting leukocytes, which includes staining cells and obtaining scattered light peak intensities and scattered light widths of respective cells based on a measured first scattered light and obtaining scattered light intensities of the respective cells based on a measured second scattered light, and obtaining fluorescence intensities of the respective cells based on the measured fluorescence light. The cells are then classified based on the scattered light peak intensities and scattered light widths.

Summary of the Invention

The invention is set out in the appended claims. The dependent claims set out particular embodiments. The embodiments or examples of the following description which are not covered by the appended claims are considered as not being part of the invention according to the description.
The invention relates to a particle sorting method, the method includes:

acquiring optical signals generated by particles irradiated with light in a blood sample when the sample passes through a detection region, the optical signals comprising at least two of forward-scattered light, side-scattered light and fluorescence;
acquiring at least one pulse width of at least one of the optical signals;
distinguishing between a first category of particles and a second category of particles according to a scatter diagram;
selecting at least one of the optical signals as a selected optical signal and using a signal intensity of the selected optical signal and the pulse width to calculate at least one reinforcement signal, depending on the number of pulse widths and/or signal intensities used for calculating the at least one reinforcement signal, the at least one reinforcement signal is a single reinforcement signal or a plurality of reinforcement signals including at least another reinforcement signal; and
forming the scatter diagram based on one reinforcement signal of the at least one reinforcement signal and at least another signal, wherein the at least another signal is either the another reinforcement signal of the at least one reinforcement signal or one of the optical signals which is different from the selected optical signa.

The invention also relates to a particle sorting device, the particle sorting device includes
an optical signal acquisition unit for acquiring optical signals generated by particles irradiated with light in a blood sample when the sample passes through a detection region, the optical signals comprising at least two of forward-scattered light, side-scattered light and fluorescence;
a pulse width acquisition unit for acquiring at least one pulse width of at least one of the optical signals;
a sorting unit for distinguishing between a first category of particles and a second category of particles according to a scatter diagram;
a calculating unit for selecting at least one of the optical signals as a selected optical signal, and using a signal intensity of the selected optical signal and the pulse width to calculate at least one reinforcement signal, depending on the number of pulse widths and/or signal intensities used for calculating the at least one reinforcement signal, the at least one reinforcement signal is a single reinforcement signal or a plurality of reinforcement signals including at least another reinforcement signal; and
a scatter diagram generating unit for forming the scatter diagram based on a reinforcement signal of the at least one reinforcement signal and at least another signals, wherein the at least another signal is either the another reinforcement signal of the at least one reinforcement signal or one of the optical signals which is different from the selected optical signal
An embodiment of the invention provides a cell analyser comprising:

a conveying apparatus for conveying a sample liquid to be tested in an optical detection apparatus;
the optical detection apparatus for irradiating the sample liquid flowing through a detection region thereof with light, collecting various optical information generated by cells in the sample liquid irradiated with light, converting the optical information into corresponding electric signals and outputting the electric signals; and
the particle sorting device mentioned above for receiving and processing the electric signals outputed from the optical detection apparatus.

In the present disclosure, a new reinforcement signal is formed by combining a function of a certain optical signal and a function of a pulse width signal so that the difference between the first category of particles and the second category of particles in the reinforcement signal is increased, and a new scatter diagram is generated based on the reinforcement signal. By means of the greater difference between the first category of particles and the second category of particles in the reinforcement signal, the first category of particles and the second category of particles can be distinguished from each other, thereby improving the accuracy of particle sorting.

Brief Description of the Drawings

Fig. 1 is an NRBC channel scatter diagram of a blood platelet aggregation sample;
Fig. 2 is a BASO channel scatter diagram of a lipid granule sample;
Fig. 3 is a schematic diagram of a detected pulse;
Fig. 4a is a forward-scattered pulse width - forward-scattered light scatter diagram of the lipid granule sample;
Fig. 4b is a forward-scattered pulse width - side-scattered light scatter diagram of the lipid granule sample;
Fig. 5 is a structural schematic diagram of a blood cell analyser;
Fig. 6 is a structural schematic diagram of a particle sorting device in an embodiment;
Fig. 7 is a structural schematic diagram of a particle sorting device in another embodiment;
Fig. 8 is an NRBC channel scatter diagram of a normal sample;
Fig. 9 is a flow chart of NRBC channel particle sorting;
Fig. 10 is an NRBC channel scatter diagram with the fluorescence signal reinforced by the forward-scattered pulse width;
Fig. 11 is an NRBC channel scatter diagram with the forward-scattered light signal reinforced by the forward-scattered pulse width;
Fig. 12 is an NRBC channel scatter diagram with the fluorescence signal reinforced by the side-scattered pulse width;
Fig. 13 is an NRBC channel scatter diagram with the forward-scattered light signal reinforced by the side-scattered pulse width;
Fig. 14 is an NRBC channel scatter diagram with the fluorescence signal reinforced by the fluorescence pulse width;
Fig. 15 is an NRBC channel scatter diagram with the forward-scattered light signal reinforced by the fluorescence pulse width;
Fig. 16 is a BASO channel scatter diagram of the normal sample;
Fig. 17 is a flow chart of BASO channel particle sorting;
Fig. 18 is a BASO channel scatter diagram with the forward-scattered light signal reinforced by the forward-scattered pulse width; and
Fig. 19 is a BASO channel scatter diagram with the forward-scattered light signal reinforced by the square of the forward-scattered pulse width.

Detailed Description of Embodiments

A particle passing through a detection region would generate a pulse, and the width of the pulse (hereinafter referred to as pulse width) can reflect the time during which the particle passes through the detection region, and thus can characterize the size of the particle. Fig. 3 shows a schematic diagram of a detected pulse, where a pulse signal is excited when a particle passes through a detection region. The pulse width is from the start of the pulse to the end of the pulse, and the pulse width signal is actually the time during which the particle passes through the detection region. When the flow rate is constant, the smaller the particle is, the shorter the time during which the particle passes through the detection region is, and in turn the smaller the corresponding pulse width will be; whereas the larger the particle is, the longer the time during which the particle passes through the detection region is, and in turn the greater the corresponding pulse width will be. Therefore, it is theoretically possible to distinguish between different kinds of particles by pulse width.
In a sample where platelet aggregation occurs, the width of a pulse generated by aggregated particles when passing through the detection region is relatively large. It is theoretically possible to distinguish between aggregated blood platelet particles and leucocytes by pulse width. However, due to the fact that the number of blood platelets aggregated together is different, the blood platelet clusters range widely in particle size, some aggregated blood platelet particles of a larger size will overlap with leucocyte groups. Therefore, the leucocytes and the aggregated blood platelet particles cannot be distinguished from each other favourably by pulse width.
With regard to lipid granules in a blood sample, because the size thereof varies, the volume thereof presents a variation from small to large magnitudes in each case. For lipid granule particles of small diameters, the corresponding pulse width is small; and for lipid granule particles of large diameters, the corresponding pulse width is large. In the case of a small pulse width, it is possible that the pulse width of a lipid granule is equal to that of a leucocyte. As shown in Figs. 4a and 4b, it can be seen that a lipid granule cluster A4 have from small to large pulse widths, and overlaps with a basophil granulocyte cluster B4 and a cluster C4 of other leucocyte particles in the small pulse width part. Consequently, the lipid granules and the leucocytes cannot be separated from each other favourably according to pulse width, no matter based on a forward-scattered light scatter diagram or on a side-scattered light scatter diagram.
Therefore, in exampless of the present disclosure, according to the difference in pulse width between the interfering particles and the leucocyte particles, a new reinforcement signal is formed by combining a function of an optical signal with a function of the pulse width signal, so that a scatter diagram generated based on the reinforcement signal can significantly enhance the effect of separating particle groups.
With reference to Fig. 5, Fig. 5 shows a structural schematic diagram of a blood cell analyser. The blood cell analyser comprises an optical detection apparatus 20, a conveying apparatus 30, a data processing device 40 and a display apparatus 50.
The conveying apparatus 30 is used to convey a sample liquid (e.g., a blood sample to be tested) after reaction with a reagent to the optical detection apparatus 20. The conveying apparatus 30 typically comprises a conveying line and a control valve, where the sample liquid is conveyed into the optical detection apparatus 20 through the conveying line and the control valve.
The optical detection apparatus 20 is used for irradiating the sample liquid flowing through the detection region thereof with light, collecting various optical information (e.g., scattered light information and/or fluorescence information) generated by cells irradiated with light, and converting the optical information into corresponding electric signals. The information corresponds to the characteristics of the cell particles and can be used as characteristic data of the cell particles. The forward-scattered light signal reflects size information of the cell, the side-scattered light signal reflects complexity of an internal structure of the cell, and the fluorescence signal reflects the content of matters in the cell that can be dyed by a fluorescent dye, such as DNA and RNA. In the example shown in Fig. 5, the optical detection apparatus 20 can include a light source 1025, a detection region 1021 serving as the detection region, a forward-scattered light signal collecting device 1023 provided on an optical axis, a side-scattered light signal collecting device 1026 and a fluorescence signal collecting device 1027 provided at a side of the optical axis. In some examples, the fluorescence signal collecting device 1027 is not required.
A blood sample is separated as needed. Streams of sample liquid after reaction with different reagents pass through the detection region 1021 of a flow chamber 1022 in sequence with shrouding by a sheath liquid. A light beam emitted by the light source 1025 is projected to the detection region 1021. Cell particles in the sample liquid are irradiated with the light beam and then emit scattered light. The light collecting device collects the scattered light, and the collected and shaped light is projected to a photoelectric sensor. The photoelectric sensor converts the optical signal into a corresponding electrical signal and outputs the electrical signal to the data processing device 40.
The data processing device 40 is configured to receive optical information output from the optical detection apparatus 20, where the optical information of each particle is used as a characteristic data set characterizing the particle, and an analysis of the blood sample is realized by analysing and processing the characteristic data of the particles. In the present example, the data processing device 40 includes a particle sorting device that generates a desired scatter diagram based on the characteristic data sets of the particles and sorts the particles according to the scatter diagram. In the examples of the present disclosure, the particle sorting device is used for distinguishing leucocytes from interfering particles, where the interfering particles may be aggregated blood platelet particles or lipid granules. In the examples of the present disclosure, the scatter diagram refers to a set of characteristic data sets of the cell particles, which may be stored in a storage device in a digitized form, or may be presented in a visualized form on a display interface.
The display apparatus 50 is electrically coupled to the data processing device 40 to display the analysis result output by the data processing device 40, and the analysis result may be a graphic, a text description, a table, or the like. In the present example, the display apparatus 50 may output various visualized scatter diagrams and/or various cell sorting results.
In one example, leucocyte particles and interfering particles are distinguished from each other by means of reinforcement signals of optical signals and pulse width signals, regardless of the presence or absence of the interfering particles and whether or not the interfering particles overlap with the leucocytes. As shown in Fig. 6, a particle sorting device includes an optical signal acquisition unit 41, a pulse width acquisition unit 42, a calculating unit 43, a new scatter diagram generating unit 44 and a sorting unit 45.
The optical signal acquisition unit 41 is used for acquiring an optical signal. When the blood sample passes through a detection region, the detection region is irradiated with light emitted by the optical detection apparatus 20, and particles in the sample are irradiated with the light to generate corresponding optical signals. The optical detection apparatus 20 collects various optical information generated by the particles due to the light irradiation. The optical signals include at least two of forward-scattered light, side-scattered light and fluorescence, for example, the forward-scattered light and the side-scattered light, or the forward-scattered light, the-side scattered light and the fluorescence.
The pulse width acquisition unit 42 is used for acquiring a pulse width of at least one optical signal. In some example, the pulse width acquisition unit 42 selects an optical signal from the collected optical signals and records the pulse width of this optical signal, for example, it can record the pulse width of the forward-scattered light, the side-scattered light or the fluorescence. In another particular example, the pulse width acquisition unit 42 selects a plurality of optical signals from the collected optical signals and records the pulse width of each of the plurality of optical signals, for example, the pulse widths of both the forward-scattered light and the fluorescence.
The calculating unit 43 is used for calculating a reinforcement signal. The reinforcement signal is calculated from the pulse width of an optical signal and a combined optical signal using a combinatorial function. The combined optical signal may be any one of the optical signals obtained by the optical signal acquisition unit 41. The combinatorial calculation increases the difference in the reinforcement signal between the leucocyte particles and the interfering particles relative to the difference between the two in the combined optical signal. For example, the reinforcement signal may be a function of the combined optical signal and the pulse width, which has an expression as follows: $Z = f (X, Y)$
where Z is the reinforcement signal; f is the function; X is the intensity of the combined optical signal, where in the examples of the present disclosure, the intensity of an optical signal can be the peak value of the optical pulse signal; and Y is the pulse width.
According to expression (1) above, the function f has the following characteristics:
the function f is monotonic for the combined optical signal or pulse width, i.e., when the combined optical signal is fixed (or constant), the function is a monotonic function for the pulse width, for example, the function is an increasing or decreasing function of the pulse width; and when the pulse width is fixed, the function is a monotonic function for the combined optical signal, for example, the function is an increasing or decreasing function of the combined optical signal.
Alternatively, the function f has the following characteristics: the function f is a non-linear combinatorial function of the combined optical signal and the pulse width.
In some example, the reinforcement signal obtained through the combinatorial calculation by the calculating unit 43 may comprise one type of signal, for example, the reinforcement signal is only a reinforcement signal of the forward-scattered light with the pulse width; the reinforcement signal obtained through combinatorial calculation by the calculating unit 43 may comprise a plurality of types of signal, for example, the reinforcement signal may be a reinforcement signal of the forward-scattered light with the pulse width, combined with a reinforcement signal of the side-scattered light with the pulse width. In some example, the optical signal of which the pulse width is recorded and the combined optical signal may be the same optical signal or may be different optical signals.
The new scatter diagram generating unit 44 is used to form a new scatter diagram on the basis of the reinforcement signal and at least another signal, and the at least another signal may be at least one optical signal different from the combined optical signal, or at least one of or a combination of two of other reinforcement signals. The new scatter diagram may be two-dimensional or three-dimensional, where at least one dimension is the reinforcement signal. In some example, a new scatter diagram is formed by selecting an optical signal and a reinforcement signal, for example, selecting one optical signal and one reinforcement signal to form a two-dimensional new scatter diagram, or selecting one optical signal and two reinforcement signals to form a three-dimensional new scatter diagram, or selecting two optical signals and one reinforcement signal to form a three-dimensional new scatter diagram. In some implementation, it is able to select an optical signal different from the combined optical signal and a reinforcement signal to form a new scatter diagram. For example, if the combined optical signal for calculating the reinforcement signal is fluorescence, the forward-scattered light and the reinforcement signal are selected to form a new scatter diagram. In another particular example, a certain reinforcement signal and other reinforcement signals are selected to form a new scatter diagram, where the other reinforcement signals refer to a reinforcement signal different from the certain reinforcement signal, for example, selecting an A-type reinforcement signal from the at least one reinforcement signal calculated by the calculating unit 43 as a dimension of the new scatter diagram, and then selecting a B-type reinforcement signal different from the A-type reinforcement signal as another dimension of the new scatter diagram. That is, the new scatter diagram selects two types of reinforcement signals to form a two-dimensional new scatter diagram, for example, selecting a reinforcement signal of the forward-scattered light and the pulse width, and a reinforcement signal of the side-scattered light and the pulse width to form a two-dimensional new scatter diagram.
The sorting unit 45 is used for distinguishing between the leucocyte particles and the interfering particles according to the new scatter diagram. Leucocyte particles and interfering particles differ slightly in optical signal and pulse width, but the difference is not sufficient to distinguish between the leucocyte particles and the interfering particles. The difference can be increased by combinatorial calculation of the optical signals and the pulse width. Since the reinforcement signal increases the difference in the reinforcement signal between the leucocyte particles and the interfering particles relative to the difference between the two in the combined optical signal, the leucocyte particles and the interfering particles can be distinguished from each other in a scatter diagram based at least on the reinforcement signal.
In another example, a conventional sorting method is used first, i.e., a scatter diagram is generated based on an optical signal, which is referred to as an initial scatter diagram. When there is an overlap region in the initial scatter diagram between leucocyte particles and interfering particles, a reinforcement signal of the optical signal and the pulse width signal are used then to distinguish between the leucocyte particles and the interfering particles. As shown in Fig. 7, a particle sorting device includes an optical signal acquisition unit 51, an initial scatter diagram generating unit 52, a pulse width acquisition unit 53, a calculating unit 54, a new scatter diagram generating unit 55 and a sorting unit 56. The optical signal acquisition unit 51, the calculating unit 54 and the new scatter diagram generating unit 55 are the same as those in the foregoing example. The initial scatter diagram generating unit 52 is used for generating an initial scatter diagram for sorting and/or counting the leucocytes according to an optical signal. The pulse width acquisition unit 53 is used for acquiring a pulse width of at least one optical signal when there is an overlap region between a leucocyte particle cluster and an interfering particle cluster in the initial scatter diagram. The sorting unit 56 is used for distinguishing between the leucocyte particles and the interfering particles and counting the leucocytes according to the new scatter diagram. When the leucocyte particle cluster and the interfering particle cluster have no overlap regions in the initial scatter diagram, the sorting unit 56 also counts the leucocytes according to the initial scatter diagram.
In the following, the disclosure is described in detail by examples of specific blood samples.
In one example, a blood platelet aggregation sample is taken as an example, the blood sample was measured by a blood cell analyser, and a leucocyte count can be obtained through an NRBC channel.
In general, red blood cells and blood platelets will form cell debris after being treated with a hemolytic agent, and the cell debris will be located in a blood ghost part of lower-end signals in the NRBC channel after measurement by the blood cell analyser. A NRBC channel scatter diagram of a normal sample is shown in Fig. 8. It can be seen that the blood ghost A5 and leucocyte cluster B5 are significantly separated from each other, so that the blood ghost will not interfere with the leucocyte counting.
When there is blood platelet aggregation in a blood sample, the hemolytic agent cannot dissolve the blood platelet favourably, so that aggregated blood platelets may remain in the blood sample, and the aggregated blood platelets have a high signal intensity and will overlap with a leucocyte group. As shown in Fig. 1, aggregated blood platelet particle group A1 and leucocyte group B1 overlap with each other, affecting the leucocyte counting through the NRBC channel.
Thus, a processing procedure of the present example is shown in Fig. 9, comprising the following blocks:
In block 61, optical signals generated by particles irradiated with light in a blood sample are acquired when the sample passes through a detection region, the optical signals including forward-scattered light, side-scattered light and fluorescence, and in the present example, the fluorescence being side fluorescence.
In block 62, a pulse width of the forward-scattered light is recorded (hereinafter referred to as forward-scattered pulse width).
In block 63, the reinforcement signal is calculated based on the pulse width. The fluorescence signal is selected as a combined optical signal, and the reinforcement signal is the product of a fluorescence signal increasing function and a pulse width increasing function, with a formula as follows: $Z 1 = fx \cdot fy$
where Z1 is a fluorescence - forward-scattered pulse width reinforcement signal, fx is an increasing function of the intensity of the fluorescence signal, and fy is an increasing function of the forward-scattered pulse width.
In some example, the signal intensity of the fluorescence signal is multiplied by the forward-scattered pulse width to obtain a fluorescence - forward-scattered pulse width reinforcement signal.
In block 64, the forward-scattered light and the fluorescence - forward-scattered pulse width reinforcement signal are selected to form a new scatter diagram. As shown in Fig. 10, the abscissa is the fluorescence - forward-scattered pulse width reinforcement signal, the ordinate is the forward-scattered light, A1 is the aggregated blood platelet particle group, and B1 is the leucocyte particle cluster.
In block 65, the particles are sorted and/or counted according to the new scatter diagram. In the present example, the leucocyte particles and the interfering particles are distinguished from each other according to the new scatter diagram. Typically, in the overlap region, the pulse width of the platelets tends to be greater than the pulse width of the leucocyte particles. According to Fig. 1, the aggregated blood platelet particle group A1 is located on the lower right side of the leucocyte particle cluster B1. In the direction of the fluorescence, where the forward-scattered light is the same, the fluorescence intensity of the blood platelet particles is greater than the fluorescence intensity of the leucocyte particles, or the fluorescence intensity at the centre of the aggregated blood platelet particle group A1 is greater than the fluorescence intensity at the centre of the leucocyte particle cluster B1. After multiplying the fluorescence intensities of the blood platelets and the leucocyte particles respectively by the pulse width, as for the multiplication of the large factors, the product will be even larger, whilst for the multiplication of the small factors, the product will be even smaller, the difference in the reinforcement signal between the blood platelets and the leucocyte particles is greater, and is increased relative to the difference in the fluorescence signal between the two. As shown in Fig. 10, the aggregated blood platelet particle group A1 is shifted more to the right relative to the leucocyte particle cluster B1, so that the overlap region between the aggregated blood platelet particle group A1 and the leucocyte particle cluster B1 is eliminated. Therefore, the leucocyte particles and the blood platelets can be distinguished from each other more easily and more accurately in the new scatter diagram.
In block 63, the forward-scattered light may also be selected as a combined optical signal, and the reinforcement signal is a quotient of a forward-scattered light increasing function and a pulse width increasing function, for example, dividing the signal intensity of the forward-scattered light by the forward-scattered pulse width to obtain a forward-scattered - forward-scattered pulse width reinforcement signal. In block 64, the side-scattered fluorescence and the forward-scattered - forward-scattered pulse width reinforcement signal are selected to form a new scatter diagram, as shown in Fig. 11. Likewise, in the overlap region, the pulse width of the platelets is greater than the pulse width of the leucocyte particles. According to Fig. 1, in the direction of the forward-scattered light, where the fluorescence is the same, the forward-scattered light intensity of the blood platelet particles is less than the forward-scattered light intensity of the leucocyte particles, or the forward-scattered light intensity at the centre of the aggregated blood platelet particle group A1 is less than the forward-scattered light intensity at the centre of the leucocyte particle cluster B1. Moreover, the reinforcement signal is the forward-scattered light intensity divided by the forward-scattered pulse width, and therefore, in the new scatter diagram, the aggregated blood platelet particle group A1 will become smaller in the direction of the reinforcement signal, while the leucocyte particle cluster B1 will become greater in the direction of the reinforcement signal, so that the difference between the leucocyte particles and the aggregated blood platelet particles is greater, and the leucocyte particles and the aggregated blood platelet particles can be distinguished from each other more easily and more accurately.
In other example, the pulse width may also be the pulse width of side-scattered light or fluorescence.
As shown in Fig. 12, the pulse width is the pulse width of the side-scattered light (referred to as side-scattered pulse width), and the reinforcement signal is the product of the fluorescence and the side-scattered pulse width (referred to as fluorescence - side-scattered pulse width reinforcement signal). The forward-scattered light and the fluorescence - side-scattered pulse width reinforcement signal are selected to form a new scatter diagram. According to the new scatter diagram, the leucocyte particle cluster B1 and the aggregated blood platelet particle group A1 can also be distinguished from each other more easily and more accurately.
As shown in Fig. 13, the pulse width is the pulse width of the side-scattered light (referred to as side-scattered pulse width), and the reinforcement signal is the quotient of the forward-scattered light divided by the side-scattered pulse width (referred to as forward-scattered - side-scattered pulse width reinforcement signal). The forward-scattered light - side-scattered pulse width reinforcement signal and the fluorescence are selected to form a new scatter diagram. According to the new scatter diagram, the leucocyte particle cluster B1 and the aggregated blood platelet particle group A1 can also be distinguished from each other more easily and more accurately.
As shown in Fig. 14, the pulse width is the pulse width of the fluorescence (referred to as fluorescence pulse width), and the reinforcement signal is the product of the fluorescence multiplied by the fluorescence pulse width (referred to as fluorescence - fluorescence pulse width reinforcement signal). The forward-scattered light and the fluorescence - fluorescence pulse width reinforcement signal are selected to form a new scatter diagram. According to the new scatter diagram, the leucocyte particle cluster B1 and the aggregated blood platelet particle group A1 can also be distinguished from each other more easily and more accurately.
Since the pulse signal can be regarded as an approximately triangular shape, and in the present example, the reinforcement signal is the product of the fluorescence multiplied by the fluorescence pulse width, the reinforcement signal can be considered to be twice the area of the fluorescent pulse signal. That is, when the combined optical signal intensity and the pulse width for calculating the reinforcement signal belong to the same optical signal, the reinforcement signal may be the area of or several times the area of the pulse signal of a certain type of light, which may be regarded as a special case of the reinforcement signal. In this case, it is to be understood by those skilled in the art that even if the area of or several times the area of the optical pulse signal are taken as the reinforcement signal, it should still be regarded as a combinatorial calculation of the signal intensity and pulse width of a combined optical signal. In addition, the area of the optical pulse signal can be calculated by multiplying a pulse peak value by the pulse width according to the area formula of a triangle, or by accumulating or integrating the optical signal within the pulse width.
As shown in Fig. 15, the pulse width is the pulse width of the fluorescence (referred to as fluorescence pulse width), and the reinforcement signal is the quotient of the forward-scattered light divided by the fluorescence pulse width (referred to as forward-scattered - fluorescence pulse width reinforcement signal). The forward-scattered light - fluorescence pulse width reinforcement signal and the fluorescence are selected to form a new scatter diagram. According to the new scatter diagram, the leucocyte particle cluster B1 and the aggregated blood platelet particle group A1 can also be distinguished from each other more easily and more accurately.
In another example, a lipid granule sample is taken as an example, the blood sample was measured by a blood cell analyser, and a leucocyte count is obtained through a BASO channel.
There is no lipid granules in a normal sample in the BASO channel, so that the leucocyte count is accurate. A BASO channel scatter diagram of a normal sample is shown in Fig. 16, where the abscissa is the side-scattered light signal, the ordinate is the forward-scattered light signal. B6 is leucocytes other than basophil granulocytes, namely lymphocytes, monocytes, neutrophil granulocytes and eosinophil granulocytes, being a main leucocyte cluster. A6 is basophil granulocytes; C6 is blood ghost, that is, fragments of red blood cells and platelets after treatment with a hemolytic agent. As can be seen from Fig. 16, there is few blood ghost spots in the normal sample, and the blood ghost are located below the main leucocyte cluster and greatly separated from the main leucocyte cluster, so that the leucocyte counting will not be interfered with.
When there are lipid granules in the blood sample, an S-shaped curve will be formed in the BASO channel, as shown in Fig. 2, where the abscissa is the side-scattered light signal, and the ordinate is the forward-scattered light signal. B2 is leucocytes other than basophil granulocytes, namely lymphocytes, monocytes, neutrophil granulocytes and eosinophil granulocytes, being a main leucocyte cluster. A2 is basophil granulocytes; C2 is blood ghost, that is, fragments of red blood cells and platelets after treatment with a hemolytic agent. In particular, at the lower end of the side-scattered light signal and the forward-scattered light signal, the lipid granules overlap with the leucocyte group and affect the leucocyte counting. Consequently, the leucocytes and the lipid granules cannot be distinguished from each other by the side-scattered light and forward-scattered light signals.
To reduce the influence of lipid granules on the leucocyte counting, a processing procedure of the present example is shown in Fig. 17, including the following blocks:
In block 71, optical signals generated by particles irradiated with light in a blood sample are acquired when the sample passes through a detection region for detection, the optical signals including forward-scattered light and side-scattered light.
In block 72, an initial scatter diagram is generated according to the forward-scattered light and the side-scattered light, where the abscissa is the side-scattered light, and the ordinate is the forward-scattered light.
In block 73, it is determined whether there is an overlap region between lipid granules and a leucocyte group in the initial scatter diagram. If there is no overlap region between lipid granules and a leucocyte group in the initial scatter diagram, as shown in Fig. 16, block 74 is performed; and if there is an overlap region between lipid granules and a leucocyte group in the initial scatter diagram, as shown in Fig. 2, block 75 is performed.
In block 74, sorting and/or counting the leucocytes according to the initial scatter diagram.
In block 75, a pulse width of the forward-scattered light is recorded (hereinafter referred to as forward-scattered pulse width).
In block 76, the reinforcement signal is calculated based on the pulse width. The forward-scattered light is selected as a combined optical signal, the reinforcement signal is the product of a forward-scattered light increasing function and a pulse width increasing function. In some example, the intensity of the forward-scattered light signal is multiplied by the forward-scattered pulse width to obtain a forward-scattered light - forward-scattered pulse width reinforcement signal.
In block 77, the side-scattered light and the forward-scattered light - forward-scattered pulse width reinforcement signal are selected to form a new scatter diagram. As shown in Fig. 18, the abscissa is the side-scattered light, the ordinate is the forward-scattered light - forward-scattered pulse width reinforcement signal, A2 is a basophil granulocyte cluster, B2 is a main leucocyte cluster, and C2 is lipid granules.
In block 78, the particles are sorted and/or counted according to the new scatter diagram. In the present example, the leucocyte particles and the interfering particles are distinguished from each other according to the new scatter diagram. As shown in Fig. 2, in the region D2 where the lipid granules overlap with the leucocyte group, the lipid granules are located on the lower right side of the main leucocyte cluster B2. In the direction of the forward-scattered light, where the side-scattered light is the same, the forward-scattered light intensity of the lipid granules is less than the forward-scattered light intensity of the leucocyte particles. As shown in Figs. 4a and 4b, at the lower end of the forward-scattered light signal, the pulse width of the lipid granules A4 is smaller than the pulse width of the main leucocyte cluster C4. After multiplying the forward-scattered light intensities of the lipid granules and the leucocyte particles respectively by the pulse width, as for the multiplication of the large factors, the product will be even larger, whilst for the multiplication of the small factors, the product will be even smaller, the difference in the reinforcement signal between the lipid granules and leucocyte particles is greater, and is increased relative to the difference in the forward-scattered light signal between the two. As shown in Fig. 18, the lipid granules C2 are shifted more to the lower right side relative to the main leucocyte cluster B2, such that there is already an apparent empty space W between the lipid granules C2 and the main leucocyte cluster B2, as shown in an enlarged view on the right side of Fig. 18. Therefore, the overlap between the lipid granules and the leucocyte cluster is avoided in the new scatter diagram, so that the leucocyte particles and the lipid granules can be distinguished from each other more easily and more accurately, thus facilitating the sorting.
In the present example, it is also possible not to determine whether or not there is an overlap region according to an initial scatter diagram, and instead, block 75 is performed directly after block 71.
In block 76, after selecting the forward-scattered light as a combined optical signal, the intensity of the forward-scattered light signal may also be multiplied by the forward-scattered pulse width to the power of N (N is greater than 1) to obtain a forward-scattered light - forward-scattered pulse width reinforcement signal, for example, multiplying the intensity of the forward-scattered light signal by the square of the forward-scattered pulse width to obtain a reinforcement signal. A new scatter diagram is formed by the side-scattered light and the reinforcement signal. As shown in Fig. 19, the lipid granules C2 are shifted more to the lower right side relative to the main leucocyte cluster B2, such that there is already an apparent empty space W between the lipid granules C2 and the main leucocyte cluster B2, as shown in an enlarged view on the right side of Fig. 19. Therefore, the leucocyte particles and the lipid granules can also be distinguished from each other more easily and more accurately according to the new scatter diagram.
In other examples, the abscissa and the ordinate of the new scatter diagram may be different reinforcement signals. For example, the abscissa is a side-scattered - forward-scattered pulse width reinforcement signal, and the ordinate is a forward-scattered - forward-scattered pulse width reinforcement signal.
In a further example, the pulse width may also be the pulse width of the side-scattered light. In block 76, the forward-scattered light may also be selected as a combined optical signal, and the reinforcement signal is a product of a forward-scattered light increasing function and a side-scattered pulse width increasing function, for example, multiplying the signal intensity of the forward-scattered light by the side-scattered pulse width to obtain a forward-scattered - side-scattered pulse width reinforcement signal. In block 77, the side-scattered fluorescence and the forward-scattered - side-scattered pulse width reinforcement signal are selected to form a new scatter diagram, where the main leucocyte cluster is shifted more to the upper left side relative to the lipid granules, such that the leucocyte particles and the lipid granules can also be distinguished from each other.
According to the above disclosure, it is to be understood by those skilled in the art that the reinforcement signal may be a function of the combined optical signal and the pulse width in order to obtain a scatter diagram that can distinguish between the leucocyte particles and the interfering particles, so long as the function increases the difference in the reinforcement signal between the leucocyte particles and the interfering particles relative to the difference between the two in the combined optical signal.
The above examples illustrate the distinguishing between leucocytes and lipid granules or aggregated PLT particles. According to the disclosed in the present application, it is to be understood by those skilled in the art that for two different categories of particles, if they differ in size in the overlap region, i.e., there are a difference in the pulse width between the two categories of particles in the overlap region, the above examples can also be used to distinguish between the two categories of particles, for example, a routine test for five types of leucocytes in certain scenes. When there is an overlap region between two categories of particles, such as lymphocytes and a monocyte cluster having an overlap region, according to different pulse widths of the particles of the lymphocytes and the monocyte cluster in the overlap region, a new reinforcement signal can also be formed using functions of an optical signal and a pulse width signal, and the lymphocytes and monocytes can be distinguished from each other based on a scatter diagram generated by the reinforcement signal, thereby obtaining a more accurate result of the five types.
It is to be understood by those skilled in the art that all or some of the blocks of the various methods in the examples described above could be achieved by hardware commanded by a program, which program can be stored in a computer-readable storage medium. The storage medium may include a read-only memory, a random access memory, a disk or an optical disk, etc.
The present disclosure has been set forth with reference to specific examples, which are merely for the purpose of facilitating the understanding of the present disclosure and are not intended to limit the present disclosure. It will be apparent to those of ordinary skill in the art that changes may be made to the specific examples described above in accordance with the teachings of the present disclosure.

Claims

A particle sorting method, comprising:
acquiring optical signals generated by particles irradiated with light in a blood sample when the sample passes through a detection region, the optical signals comprising at least two of forward-scattered light, side-scattered light and fluorescence;

acquiring at least one pulse width of at least one of the optical signals;

distinguishing between a first category of particles and a second category of particles according to a scatter diagram;

characterized by selecting at least one of the optical signals as a selected optical signal and using a signal intensity of the selected optical signal and the at least one pulse width to calculate at least one reinforcement signal, where depending on the number of pulse widths and/or signal intensities used for calculating the at least one reinforcement signal, the at least one reinforcement signal is a single reinforcement signal or a plurality of reinforcement signals including at least another reinforcement signal; and

forming the scatter diagram based on one reinforcement signal of the at least one reinforcement signal and at least another signal, wherein the at least another signal is either the another reinforcement signal of the at least one reinforcement signal or one of the optical signals which is different from the selected optical signal.
The method of claim 1, characterized in that acquiring a pulse width of at least one of the optical signals comprises:
generating an initial scatter diagram for sorting and/or counting the particles according to the optical signals; and

acquiring the pulse width of the at least one optical signal when there is an overlap region of a cluster of the first category of particles and a cluster of the second category of particles in the scatter diagram.
The method of claim 1, characterized in that the pulse width is a forward-scattered light pulse width.
The method of any of claims 1 to 3, characterized in that the reinforcement signal is a non-linear combination function of the selected optical signal and the pulse width; or the reinforcement signal is a function of the selected optical signal and the pulse width, the function being a monotonic function of the selected optical signal or the pulse width.
The method of claim 4, characterized in that the first category of particles are leucocyte particles, and the second category of particles are interfering particles that interfere with leucocyte counting.
The method of claim 5, characterized in that the optical signals are detected through a BASO channel, the optical signals comprising forward-scattered light and side-scattered light, the pulse width being a pulse width of the forward-scattered light or the side-scattered light; and preferably, the selected optical signal is forward-scattered light, and the reinforcement signal is a product of a forward-scattered light increasing function and a pulse width increasing function.
The method of claim 5, characterized in that the optical signals are detected through an NRBC channel, the optical signals comprising fluorescence and scattered light, the scattered light comprising at least one of forward-scattered light and side-scattered light, the pulse width being a pulse width of the forward-scattered light, the side-scattered light or the fluorescence; and preferably, the selected optical signal is forward-scattered light, and the reinforcement signal is a quotient of a forward-scattered light increasing function and a pulse width increasing function; or the selected optical signal is the fluorescence, and the reinforcement signal is a product of a fluorescence increasing function and the pulse width increasing function.
A particle sorting device comprising:
an optical signal acquisition unit (41, 51) for acquiring optical signals generated by particles irradiated with light in a blood sample when the sample passes through a detection region, the optical signals comprising at least two of forward-scattered light, side-scattered light and fluorescence;

a pulse width acquisition unit (42, 53) for acquiring at least one pulse width of at least one of the optical signals;

a sorting unit (45, 56) for distinguishing between a first category of particles and a second category of particles according to a scatter diagram;
characterised by:
a calculating unit (43, 54) for selecting at least one of the optical signals as a selected optical signal, and using a signal intensity of the selected optical signal and the at least one pulse width to calculate at least one reinforcement signal, wherein depending on the number of pulse widths and/or signal intensities used for calculating the at least one reinforcement signal, the at least one reinforcement signal is a single reinforcement signal or a plurality of reinforcement signals including at least another reinforcement signal; and

a scatter diagram generating unit (44, 55) for forming the scatter diagram based on a reinforcement signal of the at least one reinforcement signal and at least another signal, wherein the at least another signal is either the another reinforcement signal of the at least one reinforcement signal or one of the optical signals which is different from the selected optical signal.
The device of claim 8, characterized in that further comprising:
a scatter diagram generating unit (52) for generating an initial scatter diagram for sorting and/or counting the particles according to the optical signals;

the pulse width acquisition unit (53) for acquiring the pulse width of the at least one optical signal when there is an overlap region of a cluster of the first category of particles and a cluster of the second category of particles in the initial scatter diagram.
The device of claim 8, characterized in that the reinforcement signal is a non-linear combination function of the selected optical signal and the pulse width; or the reinforcement signal is a function of the selected optical signal and the pulse width, the function being a monotonic function of the selected optical signal or the pulse width.
The device of claim 10, characterized in that the first category of particles are leucocyte particles, and the second category of particles are interfering particles that interfere with leucocyte counting.
The device of claim 11, characterized in that the optical signals are detected through a BASO channel, the optical signals comprising forward-scattered light and side-scattered light, the pulse width being a pulse width of the forward-scattered light or the side-scattered light; and preferably, the selected optical signal is forward-scattered light, and the reinforcement signal is a product of a forward-scattered light increasing function and a pulse width increasing function.
The device of claim 11, characterized in that the optical signals are detected through an NRBC channel, the optical signals comprising fluorescence and scattered light, the scattered light comprising at least one of forward-scattered light and side-scattered light, the pulse width being a pulse width of the forward-scattered light, the side-scattered light or the fluorescence; and preferably, the selected optical signal is forward-scattered light, and the reinforcement signal is a quotient of a forward-scattered light increasing function and a pulse width increasing function; or the selected optical signal is the fluorescence, and the reinforcement signal is a product of a fluorescence increasing function and the pulse width increasing function.
A cell analyser, characterized in that the cell analyser comprises:
a conveying apparatus (30) for conveying a sample liquid to be tested in an optical detection apparatus (20);

the optical detection apparatus (20) for irradiating the sample liquid flowing through a detection region (1021) thereof with light, collecting optical information generated by cells in the sample liquid irradiated with light, the optical information comprising at least one of forward-scattered light, side-scattered light and fluorescence, converting the optical information into corresponding electric signals and outputting the electric signals; and

the particle sorting device of any one of claims 8 to 13 for receiving and processing the electric signals outputted from the optical detection apparatus.